Work Text:
Gen was acting strange.
Senku stared at the crafty fucker he called a friend. He was, in fact, a very close friend - not that you’d know it right now. There was a surface-level blankness in his eyes and his lips were carefully painted into a hesitant smile. He was holding out a selection of ores.
“Senku-chan, darling? Do you know what they are?” He asked again, tilting his head around 15 ° to the left. Strange. Gen’s natural inclination was closer to 45°.
“Yeah, of course.” The scientist pushed away his hesitation as he bent forward, closer to the rocks, squinting at them. “I think… this one’s probably bauxite? Probably bauxite. And that one’s copper, 10 billion percent. The last one… spodumene? Yeah, spodumene, if you got it from the mine we’ve been using.”
Gen nodded with keen interest. Senku was spouting science words and the mentalist’s eyes hadn’t glazed over once. Definitely strange.
“Bauxite isn’t a metal, though, is it?”
Senku shook his head. “You'd probably know it best as how we get aluminium. And spodumene is how we get lithium.”
Gen’s eyes lit up, but only for a moment, before he got himself under control. Ten billion percent strange .
“I seeeee… well, thank you!”
Before Senku could even ask what this was about, Gen had practically skipped out of the room.
So, of course, Senku followed.
“Gen! Oi, Asagiri Gen, what the fuck are you up to?” Senku called, darting out of the lab in pursuit of the weird fucking mentalist he decided to appoint as General. “Oi! Gen! Fucks’ sake, slow down!”
Not for the first time, Senku cursed the absolute pile of garbage otherwise known as his stamina. Gen had slithered off, far away, laughing and waving over his shoulder as he disappeared into the distance.
Lithium. Why did the mentalist need lithium ?
Senku stared after that pink haori, counting the uses for lithium in his head. Batteries? Armour plating? Lubricant?
His brain screeched to a halt.
Lubricant. Was Gen trying to make… lube?
Senku groaned.
Kohaku - who must have stood by and watched Senku fail to catch the mentalist instead of helping - approached the scientist cautiously.
“What was that…?” She asked, crossing her arms.
“He can’t just do that!” Senku groused, “You need to be careful about substances you’re using on your body! It’s all good and well throwing a telescope together from what you remembered, yeah, you did a great job with that but-- it wasn’t going to damage someone's health if you got it wrong! There isn’t room for error here, not one millimetre!”
“Senku, what the hell are you talking about?”
Senku’s head whipped round, red eyes meeting Kohaku's.
“Gorilla! Perfect!”
“I am not a--” she began frustratedly, but Senku cut her off.
“We have work to do!” He spun on his heel, confident strides carrying him back into the lab.
He just had to finish it before Gen did. Chemicals flew off the shelves one after another as Senku threw vial upon vial onto the table. Lithium, check. He’d need stearic acid, too. And something to make it smell better.
“Get Chrome.” He called over his shoulder to Kohaku. “I might need you to smash some stuff up later, I don’t know yet. For now I just need Chrome.”
“I can’t.” Kohaku said.
Senku glanced back over his shoulder, raising an eyebrow.
“I can’t,” she repeated, “he’s with Gen.”
Senku’s hands stilled. “He’s… what?”
“I’m pretty sure Gen went into Chrome’s place. I think I saw them go back out too, but I don’t know where they went.”
Chrome was involved in this mess? And Senku wasn't? What the fuck? Wait, were Gen and Chrome… a thing? No, surely not, Chrome was obsessed with Ruri! Anyone with eyes could see that.
Kohaku sighed, giving up. "I have no idea what's going through your head. Call me if you need me."
She left, and Senku stared at the collection of items on the workbench. What the hell was going on? Maybe he needed to re-evaluate his priorities. If Chrome was involved, Gen probably wasn’t in any immediate danger. He was, however, clearly hiding things.
Hm.
Senku felt like such a hypocrite. It had barely been any time at all since their chat, where he insisted Gen just talk to him if he wanted to know something. Yet here he was, staking out Chrome’s place, ignoring his own advice.
It wasn't his fault though! Senku was a very straightforward person. He didn't play people or hide things - if he didn't tell you something, it was because the cost in time and energy outweighed any benefits of you knowing.
Gen, on the other hand, was a master of his craft. If Gen wasn't telling him something, it was because Gen didn't want him to know. In retrospect, Senku could pick out all the signs of his secrecy - he was avoiding Senku, ducking out of Kingdom chores, and disappearing for hours on end to name but a few red flags. In fact, from the behaviours Senku had observed he could conclude Gen was trying to hide whatever he was doing (probably making lube, let’s be real) from not just him but the majority of the Kingdom.
Senku wanted to know why. Why hide it? Asking Gen would not work, it would just tip the mentalist off to the fact Senku had noticed his odd behaviour. Senku had to figure this out himself, and as a top priority - what if something was wrong? If Gen was behaving this way because a problem had arisen…
He was currently crouched in a bush - yes, he was actually crouching in a bush - and hoping desperately that when Chrome and Gen returned, there would be some convenient doorstep conversation that revealed everything. Senku had never been a lucky man, though.
He saw them before they reached the house. Chrome was decked out in all of his explorer gear, and it looked like Gen had borrowed some of that gear too. They were both grinning and laughing and covered in dirt. He couldn’t quite make out what they were saying at first, but they were both carrying shittonnes of minerals.
As they grew closer, he started to catch some of their words.
“--seriouussly baaad!” Chrome was cackling.
“It was fine in the end, though!” Gen seemed… happy? After what must have been a crazy amount of labour - they were seriously looking worse for wear - not a shred of complaining? Senku didn’t think the mentalist really minded the work that much, at least not anymore, but he would always make a fuss about it.
They got the door open and Senku missed the rest of the conversation as they slipped inside. Cursing under his breath, he left his (pathetic) hiding spot in the bushes, slinking over to the window.
Inside, the two men had dumped their haul and were now milling around, organising things into piles. There were flasks and other equipment splayed around which Senku had noticed missing from the lab. Chrome must’ve taken them!
Just as he was considering bursting into the room to shout his indignance, he felt a tug on his sleeve. Head whipping down to the source of the small force, he saw Suika staring up at him from beneath her mask.
“Did Senku notice it too?” She whispered.
Of course, Suika was already on the case. Senku wouldn’t expect anything less.
He nodded, bringing a finger to his lips. “They went out today, do you know why they’re trying to hide this?” He asked, voice in a hushed whisper. It was a good thing Ukyo wasn’t involved or they’d have been caught by now.
Suika shook her head. “Do you know what they’re doing?”
Senku shrugged, “I have an… idea, of what it might be. But if I’m right, I don’t know why they’re sneaking around.”
Suika nodded. “Leave it to Suika! Senku’s not very good at being sneaky.” Ouch. Valid, but ouch . “You should let me do this kind of thing!”
Senku nodded, “Alright, great detective Suika. Report to me in the morning, okay?”
She nodded eagerly, giving a little salute. Man, this kid was great.
Senku gave her a quiet little high-five, before retreating back towards the lab.
For the second time that day, he reorganised his priorities. Having Suika on board meant she could be head of operations for figuring-out-Gen, while he could focus his efforts on making lube. Hopefully, Gen was just embarrassed or something…? That did not seem like Gen, but it was the most logical solution he could think of. It didn’t explain why he would tell Chrome … maybe because he wasn’t a modern-timer, and wouldn’t necessarily connect lube to how Gen wanted to use it? Whatever. Suika would figure it out, probably. Or, since she wouldn’t know anything about how lube could be used either, she’d hopefully get enough clues that Senku could figure it out. If Gen was just embarrassed, then making the stuff would leave Senku one step ahead of the game! When Suika confirmed Senku’s suspicions, he could reveal that he’d known what was happening all along, present Gen with a safe to use substance, and revel in the inevitable praise.
He sighed. He didn’t believe for one second things would actually go that smoothly. Entering the lab, he was greeted by the almost-forgotten array of chemicals and tools he’d laid out earlier.
All nighter?
All nighter.
Senku awoke to small hands shaking him gently.
“Senku?” Suika.
He groaned, lifting his head from where his arm had become a make-shift pillow. He could feel drool crusted on his cheek and damp on his arm. Gross. He’d fallen asleep at the workbench in the lab...
“Suika… hey.” He murmured, rolling his neck in a sorry attempt at soothing the soreness.
“Did Senku sleep here?” Her small voice sounded worried, so Senku put on his smarmiest evil-scientist smile.
“What can I say, this new project’s just seriously exhilarating.”
She huffed what might have been a small laugh (not being able to see her face made it pretty difficult to read her, most the time) and the worry drained from her tiny shoulders. “Suika has a report!”
“Oh?” Senku sat up straighter.
“Suika will keep investigating, but” and she scooted a little closer, to speak in a whisper, “he’s been spending a lot of time at Ryuusui’s house!”
Senku’s eyebrows shot up. Ryuusui? He was sleeping with Ryuusui, was that it? This just kept getting weirder. Although, the guy was pretty attractive, in a conventional sense. And charismatic, which was a trait people were statistically attracted to in a partner. Hm.
“Okay… thanks Suika, good work. Keep it up!”
Suika nodded, offered a salute, and then she was gone.
There was one definite plus here - Ryuusui was about as crafty and sly as he was. In other words, not remotely so. He was smart, and logical, but not the type to keep secrets. If he talked to Ryuusui about this, he’d probably be able to get some answers about Gen’s behaviour. As much as he’d love to stick to the science and let Suika handle this side of things, she would hit a wall if his suspicions were right. She wasn’t about to recognise some secret fuck-buddy relationship. To Ryuusui’s, then.
Senku hopped to his feet-- and promptly sat back down. Ah, sleeping weirdly at a table all night had been bad for his muscles.
Trying again, Senku stood up more slowly. Bathe, change, and then Ryuusui’s. That was a better plan.
An hour or so later, Senku was finally on his way to the Captain’s quarters. He’d already spotted Gen caught up with some kids in the village, performing magic tricks. So, he wouldn’t have to worry about being interrupted. Perfect.
“Oi, Ryuusui, you in?” Senku called, knocking on the door as he stepped inside.
“Senku!” Ryuusui’s voice boomed from around the corner. The man stepped into sight a moment later, grinning. “To what do I owe this pleasure?”
Senku tried not to wince at the word ‘pleasure’ coming from his mouth, willing away the unwanted imagery that had sprung from some dark corner of his mind. He smiled as best he could. “Nothing good, sorry.”
Ryuusui’s brows furrowed. There were a pair of armchairs (far too nice-looking, given they were in a stone world ) in a small seating area, which Ryuusui waved to. He took a seat in one of them, and Senku took the other.
“What’s wrong?”
“You tell me.” Senku said simply. He leaned back in the seat, slouching, and folded his arms.
Ryuusui just looked very confused.
A beat of silence passed.
“Look,” Senku started, straightening up just slightly. “I know Gen’s been coming here a lot. Spending a lot of time with you, doing something that he’s hiding from me. I wanna know why.”
Ryuusui shook his head, scowling. “I don’t know what you’re talking about, Senku. I haven’t hosted Gen here in… oh, a week at least? And even then it was only to get his advice on my wardrobe, we were done in an hour or two.”
Senku narrowed his eyes, but he could sense no lie coming from the other man.
“Huh.” He deflated, glancing away from Ryuusui and chewing his lip. “Suika’s seen him here, though.”
Ryuusui rubbed at his chin. “That is very odd. You can’t ask him about it?”
Senku scoffed, “You think asking the mentalist about something he’s trying to hide would end well?”
Ryuusui snorted, nodding his head. “Best not to show your hand, I suppose.”
Just then, Francois slipped into the room. They bowed deeply, holding a silver platter perfectly straight as they did so. “Ryuusui-sama, your afternoon tea and cake.”
Ryuusui brightened, “Ah, brilliant!” He hopped to his feet, strolling over to where Francois was now setting the table for him.
Francois.
“Francois?” Senku called over his shoulder. They looked over, and Senku caught their gaze. He narrowed his eyes. “Is there a reason you’ve been hosting Gen up here?”
Francois flinched. If Senku had not been so accustomed to reading the slight changes in Gen’s body language, reading underneath layer upon layer of masks, he probably would’ve missed it. As it was, he didn’t miss a damn thing. That was a definite flinch.
“I’m not sure what you’re talking about, Senku-sama.” Francois said, poker face near-perfect. Ryuusui seemed to have noticed the flinch too though. He caught Senku’s gaze, before giving him a small nod. It was a short, sharp movement - ‘leave this to me’.
Senku shrugged. “My bad.” He stood up, resting his hands on his hips. “Nice chattin’, Ryuusui.”
“Likewise.” Ryuusui waved him off, fork in hand, and Senku took his leave.
So. Gen was probably not sleeping with Ryuusui, but might have been sleeping with… Francois? Or Francois and Ryuusui were a thing, and Gen was trying to do something nice for them by sourcing the lube? But there was ten billion percent no reason to hide that. Unless Francois and Ryuusui were a secret and that was why?
There were too many variables. Too many parameters in the equation and not enough constraints to even begin to narrow down the possibilities.
So, he was back to his pre-Ryuusui plan: let Suika keep investigating, make the lube, hope for the best.
Subconsciously, his legs had carried him back to the lab. He took stock of the state of the experiment, and remembered why he’d decided to rest his eyes the previous night. He was nearly done. These last few stages needed a steady hand and an accurate eye, which were both things he’d lost at 5am. Now, though...
Scarcely an hour later, Senku was sat at his workbench. His eyes were fixed on a simple glass vial, sat unassumingly in the centre of the table. All around the vial, papers and chemicals and other bits lay scattered. The remnants of a fierce battle, with the evidence of victory standing in the centre of the ruins.
He knew he should wait for Suika to report. Playing this slowly would be the only way to outmanoeuvre Gen. He didn’t think he could do it though. He was a patient man in many ways, but right now? Right now, he couldn’t shake the feeling Gen was doing something really, really stupid. He was more anxious than he had been in months . Now that he’d finished making the stuff, the temptation to just go and give it to Gen was way too strong. Gen wouldn’t be able to lie to him then, right? If he just made out like he was ten billion steps ahead anyway, Gen would have to come clean and explain things… right?
There was no good answer. He could wait, and risk leaving things so late that serious damage was done by Gen's probably-stupid plan. Or he could rush, and cause serious damage himself. After all, it hadn’t escaped him that Gen might have a very good reason for his secrecy. Waiting for Suika would mean he could find out if that was the case.
He huffed a heavy sigh and grabbed the vial, dropping it into his pocket as he stood up.
If there was no good answer, he’d just have to go with his gut.
His gut was screaming for answers.
He stalked through their kingdom with a scowl on his face and a fire in his eyes. The people avoided him, but he barely noticed. Arriving at Gen’s, he took a deep breath.
“Knock knock…” Senku muttered, pushing open Gen’s door. The place was empty, so he stepped inside. This might actually be perfect. He moved quietly over to where Gen’s bed roll was neatly folded away and set the vial atop the pile. He wasn’t sure he wanted to talk to Gen about his sex life anyway. This way, Gen got a safe substance and didn’t have to talk about it if he didn’t want to! That was either a perfect compromise, or the worst and most awkward thing he could do, depending on how Gen took it. Great, now he was thinking about Gen taking it and that dark corner of his mind really needed to shut the fuck up .
Looking around the room, he spotted some paper and grabbed it. He wrote a simple note: ‘you’re welcome, ask for my help next time’. Then, he was out of the room like a shot.
His heart felt lighter. This was the right choice. This was-
This was Chrome’s place, and the door was ajar. Chrome’s home was on the way to the lab from Gen’s. No one was inside.
This was… a fantastic opportunity.
Before Senku could really register what he was even doing, his feet had carried him to the door. His hands pushed it open gently.
It was as he’d seen through the window the previous night; stolen lab equipment, and piles of resources. He took a few steps closer to the equipment, brow furrowed in confusion. This… was not the right setup for making lube. Even if he accounted for the fact Chrome may not take the most efficient route to the goal, this was just--
His heart jumped into his throat.
At the end of the chain of vials and equipment, a single beaker was collecting a white powder.
C 17 H 21 NO 4. Carbon, hydrogen, nitrogen and oxygen. That was the chemical composition for cocaine, all common elements.
Had he been… had he been seriously off base here?
Was Gen... reinventing… cocaine?
It would explain the secrecy.
Behind him, Senku heard footsteps.
“Oh! Senku!” Chrome. “Oh, man, what are you doing here? Not that you’re not welcome! Course you are! I borrowed some of the lab equipment to test somethin--”
“Chrome.” Senku cut through Chrome’s blabbering. His voice was hard. He knew he shouldn’t be so tough with Chrome - Gen was the mastermind here, Chrome didn’t know how harmful recreational cocaine use could be.
“Y-yeah…?” In the silence of the room, Senku could hear Chrome swallowing. His breathing seemed off, too. Stressed. Maybe he did know.
“What the fuck are you making here?”
“I…” Chrome sighed, “I can’t tell you, Senku. It would be betraying someone’s trust.”
“Gen’s?” Senku snapped, spinning on his heel to face his apprentice.
Seeing Chrome, Senku instantly noticed how defeated he looked. His shoulders were low and his eyes were on the floor. He shook his head.
“Yeah, but someone else’s too.”
Ryuusui? Cocaine was a rich boy drug. Had Ryuusui lied to him? Was he involved, after all?
Chrome wasn’t the one to talk to, that much was clear.
With long, heavy strides, Senku stalked past Chrome and back outside.
“W-where are you going!?” Chrome yelled after him, practically tripping over himself to follow.
“Gen’s place. I’ll camp the fuck out until he gets back.”
“But--”
Gen’s home was not far. At Senku's hurried pace, it was already in sight, and Senku could see the door was open. Gen was back already then.
“But nothing, Chrome. You know what you’re making, don’t you?” He growled over his shoulder, walking faster now his true target was so close.
“Well-- yeah, kinda, I guess, but I-- look, it’ll help --”
“It won’t help a damn thing! I can’t believe Gen would actually try to convince you it would --”
“Gen, what now?” The man himself said, appearing in the doorway of his home. He was holding the small vial. Senku nearly laughed at the sight of it.
He came to a stop in front of his General, his close friend, fists clenched by his sides.
Chrome nearly ran into his back but just about managed to stop himself in time.
“He was in my house when I got back--” He began to explain to the mentalist, but Senku cut him off.
“What the hell are you playing at?” Senku hissed.
Gen titled his head to the side. 45°, this time.
“Um. Okay. One thing at a time. First, what’s this…?” He held the vial up to Senku.
“You were all excited about lithium! So obviously I thought you were trying to make lube!” Gen’s eyes widened, and he looked like he was going to choke on the air. Senku continued. “But no you’re making coke ? Seriously?! You think we can deal with--”
“Wait!” Gen cried, holding his hands up. The sheer level of exasperated confusion was almost comedic, and it was very different to his faking-it cute-innocent look. The novelty of it gave Senku pause. “I’m-- coke ? Senku, the only kind of coke I’m interested in is the cola version and you already made me that.”
“But you-- I saw it!”
“You saw--” Gen sighed, looking away. He chewed at his lip. “It’s not coke, okay?”
“Then what is it? Why are you hiding it from me?”
“How long have you been onto me?” Gen asked, a wry smile curving his lips.
“Don’t change the fucking subject, Asagiri Gen.” Senku all but snarled.
“I can’t tell you what it is but it’s not coke. Don’t you trust me?” Gen pleaded. His eyes were wide and his arms were open.
Senku groaned. “I trust you, but I also know you. Getting Chrome on board is all good and well but-- look, you can’t take risks with this stuff. Look me in the eyes and tell me you’re sure what you’re doing is safe.”
Gen looked him in the eyes, chewed his lip, then looked away.
“I fuckin’ knew it. If you don’t tell me what’s going on right now, I’m going into Chrome’s and I’m taking whatever the fuck you’ve made and I’m running every test under the sun until I--”
“Okay!” Gen looked pained. “Okay. It’s not my secret to tell, though. You have to promise me you won’t do anything with the information, other than maybe help Chrome-chan and I.”
Red eyes narrowed, looking Gen over. He wasn’t going to budge on this. Everything about his body language was open, honest and pleading. Words about trust came back to Senku's mind.
“...fine.” He conceded. Tension kept his shoulders stiff, though.
“Good. Okay. It’s…” Gen paused, then took a few steps closer to whisper in the scientist's ear, “lithium carbonate.”
Senku’s eyes widened.
Lithium... carbonate?
“What, for… bipolar disorder?”
Gen shook his head. “Come in.” He said, taking a step back again. “I’ll explain.”
Gen turned around to lead them back into his home. Senku groaned but followed after him in a hurry, Chrome close behind. They sat on the floor, and Senku stared impatiently at the mentalist.
“Well?” He prompted.
Gen sighed. “Often used for bipolar, but also used more generally to manage mania.” He searched Senku’s eyes to see how much of the puzzle he’d put together. “Ryuusui.” He said, to provide the final piece.
Senku continued to stare. “But… that doesn’t… why hide it?”
“That’s what I said!” Chrome complained, throwing his hands into the air.
“Because,” Gen huffed, “back in our time, any kind of medication for mental health was a great big red mark against pilots.”
Senku groaned, “You can’t be serious. Like I’d give a shit, he’s the best at what he does.”
“Yeah, right!?” Chrome cried. “Thank you, Senku, I knew they were being dumb!”
“Well, it wasn’t exactly my choice! Honestly, Ryuusui-chan didn’t even ask me for help. Francois-chan is the one who approached me, thinking I could help with my skills as a mentalist.” He sighed, “Unfortunately, some things just need medication.”
“And that’s when you got Chrome involved?” Senku asked.
“You were my first choice, obviously. No offense, Chrome-chan.”
Chrome snorted, “None taken.”
“But, as leader of the Kingdom, Francois was worried about--”
“How I’d take it, stopping him piloting or captaining or whatever, yeah, got it.” Senku sighed, rubbing his face.
His mouth curved up into a grin.
“Senku-chan…?”
Senku shook his head a little, laughing. A hand still covered his eyes, but his grin was perfectly visible now.
“I’m just… relieved. You’re fuckin’ stupid, trying to make something this delicate on your own, but I’m… really glad.”
Gen sniffed, “Glad I’m not making coke? Honestly, Senku-chan, I don’t understand how you could even think that of me.”
Senku peeked through his fingers to catch Gen’s gaze. “Sorry.” He mumbled. “I… yeah. That was dumb. White powder, secrecy? It just added up.”
“Funny, I seem to recall a certain scientist laughing at me jumping to conclusions not too long ago…” Gen hummed, rubbing his chin. “I wonder who that was?”
“Yeah, yeah, point taken!” Senku laughed, giving the mentalist a playful kick. Chrome snickered.
“Let’s go tell Ryuusui he’s not getting fired, hm?” Gen grinned.
Wait.
“Oh… oh, you sly fucker.” Senku muttered, moving his hand away from his face to properly lock eyes with the mentalist. “You planned this whole thing, didn’t you?”
“Why, whatever do you mean?” There it was. That oh-I’m-so-cute-and-innocent look.
“You wanted me on board but you couldn’t tell me what was happening because Francois would be mad so you just set shit up so then I’d figure it out!” Senku babbled. He scrambled to his feet, pointing an accusatory finger in the mentalists’ smug face. “Showing me those ores! Conveniently open doors! All of it was you !”
“...I really didn’t expect you to accuse me of making cocaine , though, I mean, really Senku? The lube is also a nice bonus!” Gen laughed.
Senku couldn’t find it in him to actually be mad.
He couldn’t fight the laughter that rose in response to Gen’s, so very relieved that all of this was over. Chrome joined in, and it took a few minutes for the three of them to collect themselves.
Gen had been acting strange.
Really, he should’ve realised that that in itself was strange, for a mentalist of his calibre.